This invention relates to the manufacture of door units for installation in building constructions. Doors together with their frames are typically delivered as a unit to the construction site in partial or completely prefabricated form. Such Units are referred to as “prehung” doors and they comprise a door and a doorframe, The doorframe, in turn, comprises a door jamb at either vertical side of the door and a header, the horizontal member above the door connecting the two jambs.
Hinges attach the door to one of the jambs (the hinge jamb) for opening and closing the door. The other vertical jamb is referred to as the strike jamb, as it receives the bolt on the door latch for closing and locking the door. Doors units are made to be either right opening or left opening, as needed. Left opening doors will have their hinges and hinge jamb on the right and right opening doors will have their hinges and hinge jamb on the left. Hinges and other door hardware will be placed accordingly
Two or three hinges are normally applied, spaced apart along the door side edge and jamb margin. Hinges for doors typically are butt hinges which comprise two flanges or leaves that are joined together at adjacent margins with a pin extending along the margins from the top of the flanges to the bottom to form the hinge joint. The flanges are for seating on the receiving surfaces of the door and jamb. Typically, the receiving surfaces are prepared by routing out a pocket for each flange to a depth that the outer surface of each flange is flush with the adjacent door and jamb surface.
The hinge flanges are each provided with holes therethrough for receiving screws to fix the hinge flanges to the door margin on one side and the jamb face on the other, with the hinge pin therebetween. When the hinge is closed, bringing the two flanges together, the hinge joint with its pin extends along one side of the hinge. The hinges are mounted with their pin sides to the same side of the door (the pin side) with the door edges seated so that the door may thus be opened toward the pin side.
Earlier, both of the side edges of doors had a generally flat surface that extended perpendicularly to the door face (referred to here as “square edges”). More recently manufacturers have beveled the side margin of the door on one side, the side intended to be the latch side. This bevel is typically at about three degrees inward in the direction of closing the door. This bevel is for the purpose of insuring adequate clearance between the door edge and jamb as the door is closed. However, if the door unit fabricator wishes to be able to produce units which are either left or right opening two inventories of doors must be carried, one of doors with a right side bevel and the other with a left side bevel.
To alleviate this problem, many door manufacturers now produce doors that are beveled on both side edges so that they may be used to produce either right or left opening doors, as desired. However, this, in turn, has created another problem in manufacturing the door units with the automatic equipment currently in use, as will be described.
Door units are fabricated using automated workstations, which prepare the side edge of the door and the face of a jamb for applying hinges. U.S. Pat. No. 5,222,290 of the present inventor describes one example of such a workstation. At these workstations pockets are formed in the door and door jambs for the hinges. Additionally, the workstation may have automated equipment for applying hinges on the door and door jambs at the thus prepared surfaces. The workstations are adapted to receive and hold rigidly a door, usually with the door face generally horizontally disposed, with a leading side edge of the door at a station for mortising to form hinge pockets. A door jamb is held at that location with its side edge generally parallel with the leading door side edge and with the jamb face flush with the leading side edge of the door. The jamb face and the surface of the door edge are thus essentially coplaner and thereby establish a work plane for carrying out the pocket milling operation on both the door edge and the jamb face at that location.
Typically, such workstations have one or more routers that may be moved to confront desired hinge sites along the adjacent door side edge and jamb face and to mill out the hinge pockets on the surface of the door side edge and on the jamb face at the work plane. The routers are oriented to mill the surfaces in a plane parallel with the work plane at the jamb face and the surface of the door side edge. In this manner pockets can be formed that receive the hinge flanges with the upper surfaces of the flanges flush with the jamb face and the door side edge surface.
The workstation may also have associated equipment to apply a hinge to the thus prepared hinge site at the work plane following the router operation. Screws are supplied to the screw hole sites by this equipment and automatic screwdrivers are applied to drive the screws perpendicularly to the work plane.
The foregoing equipment and procedure may be applied with good results to the traditional door edges that are not beveled, i.e. they are square, (perpendicular to the door faces). However, if the door edge is beveled, the hinge pocket will still be milled perpendicularly to the work plane, not parallel to the beveled surface. The result is that the hinge flange applied to the beveled edge of the door is, in turn, not parallel with the bevel. Consequently, the hinge flange will not be flush with the beveled surface, but, rather, partly exposed, above the beveled surface. This exposure detracts from the appearance of the door unit and may to some degree impair the attachment of the hinge to the door.
In one attempt to at least partially remedy this defect. The router is reoriented to mill at an angle that is half way between the work plane and the angle of the bevel. This compromise reduces, but does not eliminate, the exposure of the door hinge flange beyond the edge surface. And as a consequence, since milling is no longer parallel with the jamb surface, the hinge flange at the jamb face now will be partially exposed as well.
Another approach regarding this problem is that described in U.S. Pat. No. 6,561,238. A door processing machine is provided with a large tiltable section that bears a router for forming hinge pockets and the support structure for holding a jamb with its face in position for milling by the router. This section is supported by a single pivot bar extending the length of the machine parallel to the leading side edge of the door. If the leading edge of the door is square, the tiltable section is pivoted relatively to the door to bring the router into confrontation with that edge to mill it parallel with the surface of the door edge. With that positioning the router may mill parallel to both the surface of the door edge and the jamb face to produce the hinge pocket. If the leading door edge is beveled, the tiltable section may be pivoted to bring the router borne by it to an angle to mill the door edge surface parallel with that surface. The hinge pocket may thus be milled to a uniform depth to completely receive the hinge leaf with its surface flush with the door edge surface. Since the jamb is borne by the tiltable section, it will also tilt so its face is in confrontation with router at either positioning.
While with the forgoing arrangement hinge pockets parallel with the jamb face and door edge surfaces may be milled, there are significant disadvantages with this approach. It requires a radical departure from the normal workstation design. A large section of the workstation, including frame, is mounted for rotation on a single long bar. This section must not only bear the mortising assemblies but any additional equipment for operating on the juxtaposed door edge and jamb, such as a hinge applicator, including its, hinge storage and delivery equipment, screw dispenser and multiple automatic screwdrivers. Additionally this pivoting section must bear the jamb and its support equipment. Besides the complexity of this design, there can be a substantial risk that one or more of these work un-its can become misaligned due to the heavy equipment borne by this suspended section. A simpler, less expensive and more straightforward and reliable approach is needed.